This investigator-initiated R01 application (PA-07-070) proposes integrative data analysis (IDA) of existing raw data (N = 20,595 at baseline) pooled from 20 independent intervention trial studies to overcome shortcomings of individual studies and to generate a new body of knowledge to move beyond efficacy. Among individually- oriented interventions to reduce heavy drinking on college campuses, there is evidence that interventions that combine brief cognitive-behavioral skills with norms clarification and motivational enhancement, brief motivational enhancement interventions, and alcohol expectancy challenges are efficacious. However, critical questions remain unanswered with respect to how these interventions work, what may modify their effectiveness, and what secondary outcomes may be affected. This lack of clear understanding has been hampered by conceptual and design limitations of individual clinical trial studies, including relatively homogeneous samples, relatively small sample sizes, limited statistical power, limited psychometric assessment of constructs of potential mechanisms of change, and limited assessments in terms of frequency and duration under observation. The present application proposes to address these limitations of single studies by pooling data together and directly analyzing them as a single data set drawing on recent advances in psychometrics, longitudinal data analysis, and intervention evaluation methodology. This application pursues four specific aims: (1) to develop a more rigorous set of measures based on data from different studies to ensure that each measure shares a common underlying metric using a modified item response theory model, (2) to evaluate whether and when distinctive transitions in post-intervention trajectories of alcohol and drug use occur over time, and whether individual and situational differences contribute to different trajectories post- intervention, (3) to test distinctive mechanisms of change (e.g., changes in alcohol expectancies, protective strategies, readiness to change, peer norms) and to examine whether potential moderators (e.g., family history of alcoholism, gender) either facilitate or hinder post-intervention changes, and (4) to test the efficacy of alcohol interventions for drug use and other secondary outcomes. The proposed study has the potential for having a significant impact by making unique contributions to the field of alcohol intervention research for college students and, more broadly, to clinical treatment research and to the field of quantitative methodology.